A question about your PERIOD

I was wondering if anyone else had experienced this. To me, it's a great thing. I don't understand it, and that's ok... Anyway, since I had surgery, caffeine doesn't effect me as far as having cramps. The only caffeine I get is from the 16 oz of espresso I have every day and maybe if there is caffeine in the sugar free chocolate I have every so often. Before surgery, if I had a caffeinated soda or coffee, I was in some major pain, but now.... nothing. Just wondering... Thanks.